Stereophonic pick-up



I NOV. 16, 1965 05 vmzs 3,213,39

STBREOPHONIC PICK-UP Filed Nov. 16, 1960 2 Sheets-Sheet 1 Nov. 16, 1965 M. DE VRIES STBREOPHONIC PICK-UP 2 Sheets-Sheet 2 Filed Nov. 16. 1960 mvmrozc United States 2 8 Claims. ci. 179-10041 This invention relates to a stereophonic pick-up com prising a casing in which two transducers, more particularly piezo-electric transducers and a stylus holder are each locally supported, said transducers having their main faces located at least substantially at right angles to each other and the connection between the stylus holder and the two transducers being a vibration transmitting one.

in pick-ups of this type it is conventional for the vibrations pickedup by the stylus, which vibrations are taken over by the stylus holder, to be transmitted to the transducers via a coupling means. This coupling means located between the stylus holder and the transducers is mostly a two-piece element, the construction being such that the original vibrations are resolved according to two directions that are normal to each other, so that said resolved vibrations can be separately transmitted each to the appropriate transducer. Such coupling elements resolving the stylus vibrations constitute an undesirable complication in various respects and are to be considered a disadvantage of the entire construction. Said coupling elements are not only to be manufactured as separate parts, but their mounting requires special time and care. Furthermore the presence of the coupling elements stands for an undesirable increase of the vibrating mass. Moreover the known coupling elements leave to be desired, because they cannot simultaneously and with a maximum effect perform their double task, to wit the tasks of resolving vibrations and transmitting vibrations.

The object of the invention is to provide a construction in which the coupling element can be entirely omitted, because the stylus holder itself directly drives the two transducers.

It will be clear that the above-mentioned disadvantages are eliminated by this simplified construction.

According to the invention the stereophonic pick-up of the type in question is so formed that one side edge of each transducer at least locally adjoins a side edge of the other transducer, either side edge, as seen in the same direction. ending in a corner which is unsupported relative to said casing, said stylus holder being locally in r driving engagement with said two transducers at least adjacent the two unsupported corners thereof.

Furthermore the pick-up according to the invention may be so formed that the stylus holder bearing against the transducers within the angle of about 90 defined by the two transducers comprises a shank and a supporting collar embracing said shank, said stylus holder resting on said two transducers via said collar.

The pick-up according to the invention may also be so formed that the collar consists, at least partly, of a viscoclastic material.

According to another feature the pick-up according to the invention may be so formed that the stylus holder which bears against the transducers within the angle of about 270 defined by the two transducers, at least 10- cally comprises two supporting means that are about normal to each other, each of said supporting means, which may have the form of lips, bearing against one transducer.

According to another feature of the invention the supporting means of the pick-up may comprise a lining at Patented Nov. 16, 1965 the side facing the transducers, which lining consists of a layer of visco-elastic material.

According to still another feature of the invention the pick-up may also be so formed that of each of the transducers the other side edge ending in the driven unsupported corner commences in a corner which by means of a clamping piece is secured relative to the casing.

According to a further feature of the invention the pick-up may also be so formed that the two clamping pieces are united to form a bridge consisting of one piece of visco-elastic material, which bridge is provided with an extension consisting of the same material and surrounding the two transducers.

Furthermore the pick-up according to the invention may have for its feature that each transducer comprises a sleeve of visco-elastic material, which sleeve surrounds the relative crystal element and embraces both the driven unsupported comer and the corner in which the other side edge ending in said driven unsupported corner begins, the sleeve being provided with a projection secured in the casing adjacent its non-driven corner.

Furthermore the pick-up according to the invention has for its feature that adjacent the driven unsupported corner each sleeve is provided with an eye through which the stylus holder extends.

According to the invention the pick-up may be so formed that the two sleeves are formed as one whole, the two eyes being combined into one eye.

In conclusion the pick-up according to the invention may have for its feature that the collar surrounding the shank of the stylus holder is lengthened in the form of a tube extending towards the place where the stylus holder is journalled, the end of said extension forming part of a stylus holder bearing.

For elucidating the invention some embodiments of the pick-up according to the invention will be described with reference to the accompanying drawings.

in said drawings:

FIGURE 1 in perspective shows the arrangement of two transducers with their supports and with an associated stylus holder. The casing surrounding said transducers has been omitted in this figure;

FIGURES 2 and 3 are figures similar to FIGURE 1, but relate to embodiments in which the driving of the transducers by the stylus holder takes place in a different manner;

FIGURE 4 relates to a pick-up according to the invention, the casing being schematically shown in dotted lines, the interior being visible in assembled form; the driving of the transducers by the stylus holder is again different in this figure from the driving according to FlC-j URES l-3;

FIGURE 5 relates to the same construction as FIG-- FIGURE 7 is a cross-section and an elevation respec tively of the stylus holder and its bearing according to line VII-Vll in FIGURE 6.

The principle of the construction will first of all be described with reference to FIGURE 1.

Two crystal elements 1 and 2 are supported at an angle of relative to each other in a casing which is not shown. Said crystal elements 1 and 2 very closely border on each other with their side edges 3 and 4. The crystal element 1 (and exactly the same holds good for the crystal element 2), is supported at three of its corners to wit at 5, 6 and 7 by means of supporting blocks 8 and 9 which blocks consist of a visco-elastic material. Said .limited freedom of movement.

supporting blocks 8 and 9 are clampingly held in the interior of the casing (not shown) so that also the corners 5, 6 and 7 of the crystal element 1 only have a very The fourth corner 10 of the crystal element 1 is unsupported so that it is capable of following vibrations, if any, imparted thereto. A stylus holder 11 is provided with a stylus 12 at its one end in the conventional manner. The other end of the stylus holder 11 bears against the unsupported corner 10 of the crystal element 1 and likewise against the corresponding corner 13 of the crystal element 2. The stylus holder 11 is so supported between its two ends that the stylus holder can tilt in all possible directions. To said end the stylus holder 11 is provided with two plates 14 and 15 that are spaced a small axial distance apart. Between said plates 14 and 15 a bearing plate 16 is interposed, only a portion of which is shown in FIGURE 1.

Said plate 16 which is secured in the casing has a slot 16' which is wide enough for the passage therethrough of the shank of the stylus holder 11, so that the bearing plate 16 admits of being inserted between the plates 14. and 15 until the shank of the stylus holder 11 has reached the end of the above-mentioned slot 16'. The bearing plate 16 consists of a flexible resilient material, so that the stylus holder 11 can perform a tilting and seesawing movement in all directions which will cause the plate 16 to flex a little in various directions. The end of the slot is formed complementary in respect of the square shank of the stylus holder, so that the stylus holder cannot turn about its longitudinal axis. The end of the stylus-holder 11 that is not provided with the stylus comprises a block 17 by means of which the stylus holder bears against the unsupported comers 10 and 13 of the crystal elements 1 and 2. Owing to the pressure exerted by the stylus the end of the stylus holder that is frontmost in the drawing is urged upwardly, so that the rear end of the stylus holder tends to move downwardly. Because the crystal elements 1 and 2 enclose an acute angle of about 90 the rear end of the stylus holder will always move to the lowermost position under the influence of the stylus pressure. The stylus holder will come to rest when the counter-pressure exerted by the corners 10 and 13 has become equally large, which is the very thing that is aimed at. Said stylus holder therefore is self-adjusting. Seeing that the stylus holder 11 with the block 17 can only exert forces that are directed normal to the corners 10 and 13, the movements of the stylus holder are resolved in this simplest of manners into the two relatively normal directions in which the crystal elements 1 and 2 extend and in which said crystal elements yield the greatest useful effect upon being mechanically deformed.

The construction according to FIGURE 2 differs from the construction according to FIGURE 1 in that the stylus holder drives the crystal elements from the lower side. To that end the stylus holder 18 comprises two lips 19 and 20 upstanding in lateral direction and being relatively located at an angle of about 90. Said lips 19 and 20 are lined by two layers 21 and 22 which may consist, for example, of a visco-elastic material. The rear end of the stylus holder 18 is provided with an enlarged portion 23 which by means of a clamping connection is secured to the casing which again has not been shown. The stylus holder 18 consists of a resilient material which permits of flexing in all directions normal to the longitudinal direction. A resolution of the movements of the stylus holder also takes place here because the lips 19 and 20 can only transmit a force that is directed normal to the unsupported corners 24 and 25.

The construction according to FIGURE 3 closely resembles the construction according to FIGURE 1, but the manner in which the crystal elements 26 and 27 are supported is partly different. The short ends of the crystal elements 26 and 27 which extend in forward direction in this figure comprise a double sleeve 28 consisting of a visco-elastic material. The sleeve 28 has two accommodations 29 and 30 in which the crystal elements 26 and 27 fit. Furthermore the sleeve 28' comprises two projections 31 and 32 which have been partly shown and which are clampingly held in the casing. Also in this case thercfore the corners of the crystal elements 26 and 27 located adjacent the projections 31 and 32 are secured relative to the casing.

Furthermore the sleeve 28 is provided with an eye 33 into which the stylus holder 34 is tilted. A resolution of the movements of the stylus holder 34 takes place here in the same manner as in the two embodiments described hereinbefore.

In FIGURE 4 the interior of another pick-up element is shown. Two crystal elements 35 and 36 have a short side clampingly held in a common mounting block 37 which in its turn i clampingly held in the casing 38. For clampingly holding the crystal elements 35 and 36 said mounting block 37 which consists of a visco-elastic material comprises two slots 39 and 40. The casing 38 is schematically shown in FIGURE 4. Next to the mounting block 37 there is a contact block 41 likewise consisting of a visco-elastic material. For connecting the contact block 41 to the mounting block 37 the former block is provided with two pin-shaped projections 42 and 43 adapted to be fitted in openings 44 and 45 of the mounting block 37. Furthermore the contact block 41 is provided with four openings 46, 47, 48 and 49. The elements 35 and 36 comprise four connecting strips 50, 51, 52 and 53 adapted to be passed through the openings 46- 49. Four contact pins 54, 55, 56 and 57 fit in the openings 46-49 and upon being inserted into said openings they will contact the strips 50-53, said contact pins 54-57 being mounted in a supporting plate 58, consisting of an insulating material. The contact pins 54-57 may be connected, in a manner not shown, with the remainder of the installation of which the pick-up formed part. The supporting plate 58 has its upper side provided with a ridge 59 (at the lower side a similar ridge is provided), by means of which ridges the supporting plate 58 is an chored relative to the casing in the closed condition of said casing.

The corners 60 and 61 of the crystal elements are secured relative to the casing by means of a bridge piece 62 which has two accommodations 63 and 64 for the corners 60 and 61. The bridge piece 62 has its ends 65 and 66 clampingly held in the casing. A stylus holder 70 provided with a stylus 71 is inserted in a bearing made of a visco-elastic material generally designated by the numeral 72. Said bearing 73 comprises a long channel in which the stylus holder 70 is located. Said channel is formed complementary relative to the square crosssection of the stylus holder, so that said stylus holder cannot turn relative to the channel and cannot be inserted therein in a wrong position either. A spherical enlargement 73 bears against the unsupported corners 68 and.69 in the same manner as shown in FIGURE 1. Furthermore the bearing 72 comprises two discshaped enlargements 74 and 75 which axially are spaced a small distance apart. A supporting plate 76 comprises two prongs 77 and 78 adapted to he slid over the bearing 72 to lie between the disc-shaped enlargements 74 and 75. This location of the supporting plate 76 is especially visible in FXGURES 6 and 7. As appears from said figures the accommodation 67 in the supporting plate 76 is again complementary in respect of the shank portion 79 between the two enlargements 74 and 75, so that said shank portion cannot turn relative to the accommodation 67. The shank portion 79 is held in its accommodation owing to the upward pressure exerted by the stylus.

The supporting plate 76 is secured in the casing in a manner not shown. In the lower side of the casing 38 an opening not shown is provided through which the end of the stylus holder 70 carrying the stylus 71 extends from said casing.

I claim:

1. In binaural pick-ups for use with V-type record grooves wherein each side face of the groove is formed with undulations corresponding to a separate electrical signal, the combination including, two substantially iden tical elongated rectangular fiat strips of piezoelectric material, said strips having two opposite corners at one end, means to support the other ends of said strips horizontally in a casing to position the respective strips in planes substantially parallel with the respective planes of the side faces of a record groove with the lower side edge of one strip closely adjacent and parallel with the lower side edge of the other strip, means to support the upper one of the corners of said one end of each strip in a casing, stylus holder means including elongated shank means, and means to mount saidshank means in a casing for universal pivotal movement about one point along the length of said shank means and to position another point of said shank means in simultaneous separable abutting engagement with each of the lower comers of said one end of each strip.

2. The invention as defined in claim 1, wherein said stylus holder means includes a collar surrounding said shank means is provided at said another point with two laterally extending flat lip-shaped means positioned within the obtuse angle defined by said strips, each said lip being disposed in abutting engagement with said lower comer of each respective strip.

6. The invention as defined in claim 5, wherein said lipshaped means includes a strip of metal, and a layer of visco-elastic material interposed between said strip of metal and said strips of piezoelectric material.

7. The invention as defined in claim 1, wherein said means to support said upper corner at said one end of 4 with undulations corresponding to a separate sound vihr.1-

tion signal, the combination including, two substantially identical elongated rectangular flat strips of piezoelectric material, said strips having two opposite corners at one end, means to support the other ends of said strips horizontally in a casing to position the respective strips in planes substantially parallel with the respective planes of the side faces of a record groove with the lower side edge of one strip closely adjacent and parallel with the lower side edge of the other strip, stylus holder means including an elongated shank, means to mount said shank in a casing for universal pivotal movement about a point medially of its length, a generally V-shaped unitary element of visco'elastic material comprising a pair of sleeves for encircling said one end of both said strips and including an opening adjacent the lower corners of said one end of said strips for-receiving one end of said stylus holder shank, said unitary element also including a pair of laterally outwardly projecting portions for supporting the upper corners of said one end of each of said strips.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 12/ 1956 Germany. 6/1959 France.

5/1960 Great Britain.

IRVING L. SRAGOW, Primary Examiner.

STEPHEN W. CAPELLI, BERNARD KONICK,

Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,218,399 November 16, 1965 Machiel de Vries It is hereby certified that error eppeere in the above numbered petent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 39, strike out "11,092 12/1956 Gemm line 40, for "180,858 6/1959 France" read 1,180,858 6/1959 France after line 41, insert the following OTHER REFERENCES r n Printed Application, Batsch T-1l,092, Dec. 13, 1956 Signed and sealed this 20th day of September 1966. :SEAL) m1 W. swmEa EDWARD J. BRENNER ltteslingoffioer Commissioner ofPatenm 

8. IN BINAURAL PICK-UPS FOR USE WITH V-TYPE RECORD GROOVES WHEREIN EACH SIDE FACE OF THE GROOVE IS FORMED WITH UNDULATIONS CORRESPONDING TO A SEPARATE SOUND VIBRATION SIGNAL, THE COMBINATION INCLUDING, TWO SUBSTANTIALLY IDENTICAL ELONGATED RECTANGULAR FLAT STRIPS OF PIEZOELECTRIC MATERIAL, SAID STRIPS HAVING TWO OPPOSITE CORNERS AT ONE END, MEANS TO SUPPORT THE OTHER ENDS OF SAID STRIPS HORIZONTALLY IN A CASING TO POSITION THE RESPECTIVE STRIPS IN PLANES SUBSTANTIALLY PARALLEL WITH THE RESPECTIVE PLANES OF THE SIDE FACES OF A RECORD GROOVE WITH THE LOWER SIDE EDGE OF ONE STRIP CLOSELY ADJACENT AND PARALLEL WITH THE 